spacetoday.net: Air bubbles in foam could have contributed to Columbia accident

Posted: Thu, Mar 27, 2003, 1:56 PM ET (1856 GMT)
STS-107 patch (NASA)

Shuttle investigators said this week that air bubbles in insulating foam on the shuttle’s external tank may have made it easier for the foam to fall off and strike the shuttle during launch. Investigators said they discovered air bubbles in foam on an external tank at the Michoud, Louisiana facility where the tanks are built. The bubbles could make it easier for the foam to come off during flight; it could also provide a place for ice to form within the foam itself, increasing the density and mass of any chunks that fell off the tank. Investigators plan to test the foam impact theory by firing pieces of foam at pieces of the thermal protection systems taken from the shuttles Enterprise and Discovery. If the foam is at fault, it could take a considerable amount of time to affect changes to the foam itself: the Dallas Morning News reported this week that NASA officials said it normally takes "four to five years" to make changes in the foam insulation, although that process could be accelerated somewhat.